April 15, 2015

The Search for a Single-Nutrient Solution to Mental Illnesses Is Outdated

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Bonnie J. Kaplan, PhD and Julia J. Rucklidge, PhD

University of Calgary, Calgary, Alberta, Canada (Dr Kaplan) and University of Canterbury, Christchurch, New Zealand (Dr Rucklidge)


Our previous blog entry showed that the knowledge that good nutrition is essential for mental health is very old. Here, we would like to talk about the misguided approach taken by many scientists over the last century of looking for a single nutrient that will have profound effects on brain function.

Two reviews we have conducted of the scientific literature on the use of vitamins and minerals for the treatment of mood disorders and ADHD found dozens of reports from about 1910 to the present. Many nutrients have been studied, including the B vitamins; vitamins C, D, and E; and calcium, chromium, iron, magnesium, zinc, selenium, choline. But scientists were not studying nutrition in the way in which humans have evolved to require nutrients, ie, consumed together and in balance. Studies generally followed a “drug trial model” by giving patients a single nutrient and seeing if their symptoms improved.

Experimental science has made great progress by adhering to the principle that only one variable can be altered at a time and all other variables must be controlled. This approach aided the post–World War II golden era of drug development. A few decades ago, though, psychologists demonstrated the value of complex independent variables, investigating multivariable, usually manualized, treatments such as cognitive-behavioral therapy. The two of us thought this debate was over and that, especially in the realm of nutrition, multivariable treatments were accepted. But one of Julia’s manuscripts on multinutrient treatment was rejected recently by a leading American psychiatry journal with one reviewer complaining, “We can’t tell which is the active ingredient.”

Has the single-nutrient, “magic bullet” approach to mental illness yielded benefits? Yes, but the benefits are consistently modest. Calcium supplementation modestly improves mood; zinc or copper supplementation modestly improves mood and can improve attention; and various B vitamins administered singly modestly improve mood. Some recent research suggests that omega-3s or vitamin D administered in isolation can improve some psychiatric symptoms to a modest degree.

We acknowledge that for some physical illnesses, single nutrients can mean life or death. Scurvy is a great example of this because vitamin C can prevent and cure it. Pellagra and its psychosis can be cured with niacin therapy (more on that in our next blog entry). Also, vitamin B12 can completely eradicate pernicious anemia, an illness that often presents with psychiatric symptoms. And, what woman in the Western world who is planning a pregnancy is unaware of the need to take folic acid to prevent birth defects, although other B vitamins have also been shown to be beneficial?

What is troubling about the single-nutrient literature is that hundreds of studies and millions of research dollars have been wrongly based on the idea that a treatment must consist of just one nutrient at a time. The esteemed nutrition researcher Walter Mertz understood the fallacy in this way of thinking. Twenty years ago, he declared that all of the single-nutrient–related diseases had most likely been identified and that all future discoveries of health-related nutrition would consist of complex nutrient formulas. In the last decade or so, studies of broad spectrum or complex nutrient treatments have been conducted. We hope our future blog entries will convince you that broad-based nutrient supplementation is the most logical treatment of illnesses such as dysregulated mood, obsessions, impulsivity, hallucinations, and scattered attention, to name a few.

This blog entry is adapted from a previous entry that can be found at

Financial disclosure:Drs Kaplan and Rucklidge had no relevant personal financial relationships to report, and no company has ever funded any of their studies.

Category: Medical Conditions , Mental Illness , Psychosis
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4 thoughts on “The Search for a Single-Nutrient Solution to Mental Illnesses Is Outdated

  1. Wonderfully articulated. I was a chiropractor before becoming a family nurse practitioner (first) and subsequently a psychiatric nurse practitioner–so my first and abiding love was/is nutrition and natural remedies to treat illnesses. As such, I’m always looking at research, but what I have to admit to myself and to patients is that there is no answer there (yet?), and, as you wrote, outcomes are generally better when nutrition is optimum–but it would be folly at this point to rely exclusively on vitamins and minerals alone to treat mental illnesses. It will be a happy day indeed when and if we come to more nutritional answers, and I hope I’m alive (and have my wits about me!) to see it.
  2. Good article. Taking it a step further, separating the body into discrete “targets” with respect to nutrients is fallacious. What is good for the heart is also good for the brain, the bones, the skin, the prostate, liver, etc. Rather than a magic bullet, the real answer, as far as nutrition is concerned, is a shotgun blast of whole plant foods. There are hundreds of thousands of phytonutrients. Research has identifed some, such as sulporaphonae in broccoli and ECGC in green tea, that are proven to possess potent health benefits. But it isn’t necessary to understand the exact mechanisms to derive the benefits. If one eats the widest possible variey of fruits and vegetables, one can’t help but to ingest bullets that scientists may never be aware of.
  3. Thanks for all the comments.
    ercurry: We agree that the field needs more research. However, we reviewed all studies that had been conducted on broad spectrum micronutrients a couple of years ago and were surprised to find that there have already been over 20 RCTs (the gold standard used to make clinical decisions) using micronutrients in treating psychiatric symptoms with positive results. See:
    • Rucklidge, J. J., & Kaplan, B. J. (2013). Broad-spectrum micronutrient formulas for the treatment psychiatric symptoms: A systematic review. Expert Review of Neurotherapeutics, 13(1), 49-73.
    While there are a number of studies documenting the benefits of micronutrients in treating serious psychiatric problems like bipolar disorder, we need replication with more rigourous studies.

    In reply to ksteinbach, we agree it is much better to get nutrients from food given the additional compounds present beyond just minerals and vitamins. However, there aren’t any studies to date that can direct us to know whether dietary manipulation alone can result in positive health benefits or whether one needs additional nutrients than what we can get out of food.

    Finally in reply to mainak1: A student of Julia’s, Amy Romijn, just reviewed this literature (look out for Romijn, A. R. & Rucklidge, J. J. (in press). Psychobiotics: Does the evidence support the theory? A systematic review. Nutrition Reviews coming out later this year) and we were surprised to find that there haven’t been many studies using probiotics to treat people with psychiatric symptoms although there are some conducted with “healthy” individuals showing benefit of probiotics in improving mood and cognition. We need a lot more research in this area.

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